Many systems, such as wireless telephone base stations, employ multiple power transistors, such as LDMOS (Laterally Diffused MOS) transistors, to amplify a signal for transmission, e.g. a radio frequency (RF) signal. Typically, the biasing for the power transistors is implemented using discrete devices that must be hand tuned for the particular application and the characteristics of the particular transistors employed. This is an expensive approach both in terms of parts costs and labor costs. In addition, the resulting bias level is typically either fixed for the lifetime of the system or must be retuned by hand to account for the effects of aging and temperature. U.S. Pat. No. 5,710,519 describes an example of a prior art device and is hereby incorporated by reference for all purposes.